Default Shader - Opacity Tab

Description:
The Opacity tab has settings which effect the opacity of the shader. It might help to think of opacity as being the opposite of transparency.

Settings:

Opacity: This sets the overall opacity of the shader. A value of 1 means the shader is fully opaque. A value of 0 means the image is fully transparent.

Opacity image: You can use this to select an image file to control opacity.

Use alpha channel: If this is checked the alpha channel from the specified image file will be used for opacity rather than the colour channels.

Invert opacity image: If this is checked the opacity image is inverted i.e. black becomes white.

Opacity function: This parameter lets you control opacity using other nodes.

Alpha from colour: If this is checked then the shader will generate opacity based on a colour from the image specified in the Colour imageparameter and/or the shader connected to the Colour functionparameter. The colour used for opacity is set with the Alpha keyparameter.

Alpha key: This sets the colour used to generate opacity. For example if you want green areas to be transparent you would set the alpha key to green.

Key tolerance: This controls how many shades of colour similar to the Alpha key colour are used to generate opacity.

A shader is a program or set of instructions used in 3D computer graphics to determine the final surface properties of an object or image. This can include arbitrarily complex descriptions of light absorption and diffusion, texture mapping, reflection and refraction, shadowing, surface displacement and post-processing effects. In Terragen 2 shaders are used to construct and modify almost every element of a scene.

A parameter is an individual setting in a node parameter view which controls some aspect of the node.